title(x5(n),p=15,q=8);
y4=fft(x4,16);
subplot(4,2,8);
stem(n,abs(y4),.);
axis(0,20,0,4);
title(FFT,p=15,q=8);
生成波形为：（3）衰减正弦序列及其不同采样频率时的FFT：n=0:50;
x1=50*exp(-0.1.*n).*sin(62.5*pi/500*n);
subplot(2,2,1);
stem(n,x1,.);
axis(0,50,-20,40);
title(x7(n),fs=1000Hz);
y1=fft(x1,51);
subplot(2,2,2);
stem(n,abs(y1),. 。

17、);
axis(0,50,0,250);
title(FFT,fs=1000Hz);
x2=50*exp(-1/3.*n).*sin(62.5*pi/150*n);
subplot(2,2,3);
stem(n,x2,.);
axis(0,50,-20,40);
title(x7(n),fs=300Hz);
y2=fft(x2,51);
subplot(2,2,4);
stem(n,abs(y2),.);
axis(0,50,0,150);
title(FFT,fs=300Hz生成波形为：（4）载波调制解调信号t=0:0.01:3;
x=cos(pi*t).*cos(9*pi*t);
plot(t,x);
axis(0。

18、3 -2 2);
grid;
title(x5(t)=cos(pi*t)*cos(9*pi*t)t=0:0.01:3;
x=cos(pi*t);
plot(t,x);
axis(0 3 -1 1);
grid;
title(解调信号)（5）无限长序列n=0:100;
x=0.8.n;
subplot(1,1,1);
stem(n,x,.);
axis(0 100 0 1);
title(x6(n)=0.8n)n=0:9 x1=0.8.n;
subplot(2,2,1);
stem(n,x1,.);
axis(0,20,0,1);
title(序列x6(n),M=10);
y1=fft(x1,10);
subplo 。

19、t(2,2,2);
stem(n,abs(y1),.);
axis(0,20,0,3);
title(M=10,FFT,幅频特性);
m=0:19 x2=0.8.m;
subplot(2,2,3);
stem(m,x2,.);
axis(0,20,0,1);
title(序列x6(n),M=20);
y2=fft(x2,20);
subplot(2,2,4);
stem(m,abs(y2),.);
axis(0,20,0,3);
title(M=20,FFT,幅频特性)（二）、数字滤波器的设计与实现采用双线性变换法设计IIR数字滤波器：源程序：低通：global fpglobal fsglobal apgloba 。

20、l asglobal Fswp=2*pi*fp/Fs;
ws=2*pi*fs/Fs;
Ts=1/Fs;
wp1=2/Ts*tan(wp/2);
ws1=2/Ts*tan(ws/2);
N,Wn=buttord(wp1,ws1,ap,as,s);
Z,P,K=buttap(N);
Bap,Aap=zp2tf(Z,P,K);
b,a=lp2lp(Bap,Aap,Wn);
bz,az=bilinear(b,a,Fs);
figure(1)freqz(bz,az);
y,t=impz(bz,az,50);
figure(2)stem(t,y,.);
高通：global fpglobal fsglobal apgl 。

21、obal asglobal Fswp=2*pi*fp/Fs;
ws=2*pi*fs/Fs;
Ts=1/Fs;
wp1=2/Ts*tan(wp/2);
ws1=2/Ts*tan(ws/2);
N,Wn=buttord(wp1,ws1,ap,as,s);
Z,P,K=buttap(N);
Bap,Aap=zp2tf(Z,P,K);
b,a=lp2hp(Bap,Aap,Wn);
bz,az=bilinear(b,a,Fs);
figure(1)freqz(bz,az);
y,t=impz(bz,az,50);
figure(2)stem(t,y,.);
带通：global fp1global fp2global。

22、fs1global fs2global apglobal asglobal Fswp1=2*pi*fp1/Fs;
wp2=2*pi*fp2/Fs;
ws1=2*pi*fs1/Fs;
ws2=2*pi*fs2/Fs;
B=ws2-ws1;
w0=sqrt(ws1*ws2);
wp=max(abs(wp1),abs(wp2);
ws=1;
N,wc=buttord(wp,ws,ap,as,s);
num,den=butter(N,wc,s);
numt,dent=lp2bp(num,den,w0,B);
numd,dend=bilinear(numt,dent,1);
w=linspace(0,pi,512);
figur 。

23、e(1)freqz(numd,dend,w);
y,t=impz(numd,dend,50);
figure(2)stem(t,y,.)；带阻：global fp1global fp2global fs1global fs2global apglobal asglobal Fswp1=2*pi*fp1/Fs;
wp2=2*pi*fp2/Fs;
ws1=2*pi*fs1/Fs;
ws2=2*pi*fs2/Fs;
B=ws2-ws1;
w0=sqrt(ws1*ws2);
wp=max(abs(wp1),abs(wp2);
ws=1;
N,wc=buttord(wp,ws,ap,as,s);
num,den=butter 。

24、(N,wc,s);
numt,dent=lp2bs(num,den,w0,B);
numd,dend=bilinear(numt,dent,1);
w=linspace(0,pi,512);
figure(1)freqz(numd,dend,w);
y,t=impz(numd,dend,50);
figure(2)stem(t,y,.);
生成波形为：低通及其单位脉冲响应：高通及其单位脉冲响应：带通及其单位脉冲序列：带阻及其单位脉冲响应：（三）、综合应用语音信号的分析处理源程序：读入语音信号：x1,fs=wavread(C:tada.wav);
sound(x1,fs);
fs y1=fft(x1,1024);
。

25、 f=fs*(0:511)/1024;
figure(1)plot(x1) title(原始语音信号);
xlabel(time n);
ylabel(fuzhi n);
figure(2)freqz(x1) title(频率响应图)figure(3)subplot(2,1,1);
plot(abs(y1(1:512) title(原始语音信号FFT频谱)subplot(2,1,2);
plot(f,abs(y1(1:512);
title(原始语音信号频谱)xlabel(Hz);
ylabel(fuzhi);
语音信号低通处理：global fpglobal fsglobal apglobal asx1,Fs 。

26、=wavread(C:tada.wav);
t=0:1/Fs:(size(x1)-1)/Fs;
Fswp=2*pi*fp/Fs;
ws=2*pi*fs/Fs;
Ts=1/Fs;
wp1=2/Ts*tan(wp/2);
ws1=2/Ts*tan(ws/2);
N,Wn=buttord(wp1,ws1,ap,as,s);
Z,P,K=buttap(N);
Bap,Aap=zp2tf(Z,P,K);
b,a=lp2lp(Bap,Aap,Wn);
bz,az=bilinear(b,a,Fs);
H,W=freqz(bz,az);
figure(1)plot(W*fs/(2*pi),abs(H)gridxlabel 。

27、(频率Hz)ylabel(频率响应幅度)title(Butterworth)f1=filter(bz,az,x1);
figure(2)subplot(2,1,1)plot(t,x1);
title(滤波前的时域波形);
subplot(2,1,2)plot(t,f1);
title(滤波后的时域波形);
sound(f1,22050);
F0=fft(f1,1024);
f=Fs*(0:511)/1024;

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标题：数字信号|数字信号处理课程设计报告( 三 )